The standard ultrasonic device for atomizing liquids is normally comprised of a single atomization unit wherein an upward directed liquid covered ultrasonic transducer is located at the bottom of the unit and the top of the unit is open (covered by a gas). These known devices have numerous operational problems which prevent them from being used in many applications. These problems exist because each element of the standard known device presents specific operational limitations.
First, ultrasonic transducer will almost instantaneously thermally overheat if exposed to air (or gas) during operation. Movement of the standard devices may result in tipping of the liquid level above the transducer such that the transducer may become exposed to air or gas. Placing of a sufficient (taller) column of liquid above the transducer may help to solve the device mobility problem, but it adversely affects the operational efficiency of the transducers.
Second, the vibrating surface of the ultrasonic transducer is adversely affected by accumulated precipitates and impurity coatings (deposits) caused by the liquid environment. These coatings often deteriorate transducer efficiency and create a thermal insulation layer which eventually results in the transducer thermally overheating.
Impurities in liquids have many sources. Often impurities may be initially present in the liquids. Impurities may enter into the liquid through contact with the air (or gas). Sometimes impurities are a result of interactions between the liquid and components of the device (e.g. pumps, gaskets, etc.). Furthermore impurities may be produced by the interaction process with the transducer (e.g. from the ultrasonic waves, chemical interactions, or electrolysis). These impurities often aggregate, and further contribute to the accumulation of coatings (deposits) on the transducers.
Third, use of multiple transducers within the same atomization unit (to increase the atomization rate and output) results in liquid turbulence affects on the transducers (including destructive electrical etching phenomena).
The device of the present invention overcomes the above mentioned disadvantages, allows device location transfer (without risking transducer exposure), and prevents impurity accumulation.
Furthermore, most known atomization devices produce a broad statistical distribution of droplet sizes. This has disadvantages in applications requiring ultra-accurate delivery systems (e.g. medicines, disinfectants, fungicides, etc.). One embodiment of the device of the present invention is especially for allowing production of a narrow statistical distribution of about 0.5 to 5.0 micron diameter droplets.